The development of efficient and durable electrodes for anion exchange membrane water electrolyzers (AEMWEs) is essential for hydrogen production. In this work, 2D NiFe layered double hydroxides (NiFe LDHs) nanosheets were grown on the 1D cobaltous carbonate hydroxide nanowires array (Co-OH-CO₃) and the unique 3D layered self-supporting nanorod array (NiFe LDHs@Co-OH-CO₃/NF) electrode was obtained. Importantly, we demonstrated an efficient and durable self-supporting NiFe LDHs@Co-OH-CO₃/NF electrode for oxygen evolution reaction (OER) and as the anode of the AEMWE. In a three-electrode system, the self-supporting NiFe LDHs@Co-OH-CO₃/NF electrode showed excellent catalytic activity for OER, with an overpotential of 215 mV at a current density of 20 mA·cm^-2 in 1 mol·L^-1 KOH, and the promising AEMWE performance upon using as the anode, with a current density of 0.5 A·cm^-2 at 1.72 V in 1 mol·L^-1 KOH at 70 ℃. The experimental results further revealed the outstanding performance of the electrode with the special morphological structure. The 3D layered structure of nanorod array electrode could effectively prevent the agglomeration of nanosheets, which is conducive to electron transfer and provides a large number of edge active sites for water electrolyzer.

Bimetallic platinum-copper (Pt-Cu) alloy nanowires have emerged as a novel class of fuel cell electrocatalysts for oxygen reduction reaction (ORR) due to their intrinsic high catalytic activity and durability, but preparing such electrocatalysts with clean surface via facile method is still a challenge. Herein, PtCu alloy with nanowire networks (NWNs) structure is obtained by a simple modified polyol method accompanied with a salt-mediated self-assembly process in a water/ethylene glycol (EG) mixing media. The formation mechanism of PtCu NWNs including the morphological evolution and the relevant experimental parameters has been investigated systematically. We propose that a micro-interface in H₂O-EG media formed with the assistance of disodium dihydrogen pyrophosphate (Na₂H₂P₂O₇) and its unique nature of coordinating with Pt²⁺ or Cu²⁺ play critical roles in the formation of NWNs. When tested as ORR catalyst, the PtCu_NWNs/C exhibits much higher activity and durability than that of Pt_NWNs/C and commercial Pt/C, even exceeding the target of DOE in 2020. The excellent performance of PtCu_NWNs/C could be attributed to the unique structure of NWNs with 2.4 nm ultrathin wavy nanowires and plentiful surface defects and the modified electronic effect caused by alloying with Cu atoms.